Various valve structures have been proposed for use with bottles and cans and other receptacles, with the structure having a valve member that is adapted to open as a receptacle is tipped for pouring and closed when the receptacle is returned to the upright position. One such structure is shown in U.S. Pat. No. 2,581,897 which discloses a valve assembly having a valve head which moves under the influence of gravity to open and close a receptacle. When the valve is maintained in the upright position the valve head maintains a seal with the valve seat due to the weight of the valve head and upon tipping of the valve the head becomes unseated and the contents of the container may be poured. Although this structure is automatic in that the user does not have to activate the valve separately, it has some inherent drawbacks in that the valve must always be maintained in the upright position for sealing and in that the valve relies on the weight on the valve head for providing a seal. Furthermore, any build up of pressure within the receptacle will reduce the force maintaining the seal and may result in leakage of gas from the receptacle.
A magnetic closing device is shown in U.S. Pat. No. 2,672,257 but, the device is not automatic in that the user must manually open the valve prior to tipping of the receptacle. The reference does disclose how a magnetic base portion may be used with a cap made from a magnetic attractable material, such that upon closing of the cap the seal is maintained by the magnetic attraction between the base magnet and the cap material.
The present invention provides a fully automatic valve closing device which is opened when the receptacle is tipped for pouring and closed when the receptacle is returned to the initial position, while overcoming the problems associated with the gravity operated system disclosed in U.S. Pat. No. 2,581,897.